If you are searched during police hours and you have no drugs on you, you will be fined 50$ and returned to the main apartment.
If you are searched during police hours and you are caught with drugs, you will be fined 100$ and will be release in the morning.(7:00 to 21:00).
If you attempt to evade police and are caught, you will also be jailed and fined, spending several hours in jail. At night, you will be jailed until the morning.
You can lower your exposition and risk factors and make yourself an overall smaller target for the police by completing things like deals, dead drops, cartel drops, etc. at night. Completing these actions at night will also give you bonus experience and will give you an extra bit of money as "hazard pay".